The list_cats WordPress PHP Filter allows you to modify taxonomy drop-down display elements just before they are displayed. You can filter arguments such as ‘show_option_none’, ‘show_option_all’, and various forms of the term name.
Usage
add_filter('list_cats', 'your_custom_function_name', 10, 2);
function your_custom_function_name($element, $category) {
// your custom code here
return $element;
}
Parameters
$element(string): Category name.$category(WP_Term|null): The category object, or null if there’s no corresponding category.
More information
See WordPress Developer Resources: list_cats
Examples
Add a custom prefix to category names
This example adds the text “Category: ” as a prefix to each category name.
add_filter('list_cats', 'add_prefix_to_category_names', 10, 2);
function add_prefix_to_category_names($element, $category) {
$element = 'Category: ' . $element;
return $element;
}
Display category ID next to category name
Display the category ID next to the category name in the drop-down.
add_filter('list_cats', 'display_category_id', 10, 2);
function display_category_id($element, $category) {
if ($category) {
$element .= ' (' . $category->term_id . ')';
}
return $element;
}
Uppercase category names
Transform all category names to uppercase in the drop-down.
add_filter('list_cats', 'uppercase_category_names', 10, 2);
function uppercase_category_names($element, $category) {
$element = strtoupper($element);
return $element;
}
Show category count next to category name
Display the number of posts in each category next to the category name.
add_filter('list_cats', 'show_category_count', 10, 2);
function show_category_count($element, $category) {
if ($category) {
$element .= ' (' . $category->count . ')';
}
return $element;
}
Remove empty categories
Hide categories with no posts from the drop-down.
add_filter('list_cats', 'hide_empty_categories', 10, 2);
function hide_empty_categories($element, $category) {
if ($category && $category->count > 0) {
return $element;
}
return '';
}